I've been sitting on this unbelievably gripping, humorous, and intellectually stimulating lecture by Robert Sapolsky for months now. I'm not sure why. My work life whisked me away, but, in watching this video again, it's too good not to share.

Sapolsky is one of the world's leading neuroscientists who explores "the biology of neurons" and how stress factors in to our social lives. He's an incredible storyteller who makes sense of the human species by studying primates, particularly baboons. Using many examples from the wild, he debunks a series of commonly held assumptions that most people believe define human beings as being distinct, as being unique to our species: theory of mind, the Golden Rule, empathy, tit-for-tat, etc.

Despite all the universal behaviors we humans hold in common with other animals, Sapolsky says that humans have one trait that best defines and distinguishes us from other species: the ability to hold two contradictory ideas in our head, and yet continue on in the face of it.

During a staff meeting several months ago, I recommended that one of our associate producers do some research on Dr. Sapolsky as a potential interview with Krista. The feedback: Dr. Sapolsky was a good storyteller with great depth of experience, but there was concern that his atheism might be too strident and might not work for our program.

To me, it's these types of voices that we want to include in our repertoire of shows. He's a non-believer who embraces the paradox himself. He's not just against religion or worshiping a deity. He lives an intellectual life that listens to these religious and philosophical voices and internalizes them. He takes them seriously and doesn't dismiss them.

So, when I'm evaluating future guests, I'm looking for clues, for indicators that strike me as openness to ideas without personally accepting them as doctrine. So, even though Dr. Sapolsky declares himself strident in the lecture above, he makes a Niebuhrian statement like the one that heads the top of this page. And, shortly thereafter, posts a slide with a quotation from Danish philosopher and theologian Søren Kierkegaard:

"Christian faith requires that faith persists in the face of the impossible, and that humans have the capacity to simultaneously believe in two contradictory things."

"The less forgivable the act, the more it must be forgiven. The less loveble the person is, the more you must find the means to love them."

What's even more delightful is Sapolsky's own ability and intellectual curiosity to live comfortably and reconcile his own positions and beliefs. He marvels:

"As a strident atheist, this strikes me as the most irrational, magnificent thing we are capable of as a species. … And this one does not come easily. On a certain level, the harder this is, this contradiction, to take the impossibility of something and to be the very proof that it must be possible and must become a moral imperative, the harder it is to do that, the more important it is."

In the bottom photo, Sister Helen Prejean participates in a demonstration against the death penalty in Paris, France on July 2, 2007. (photo by Mehdi Fedouach/AFP/Getty Images).

Robert Sapolsky would be a brilliant guest. I encourage you to re-engage the people who sense his atheism might be too strident. The change to Being should open up options like this a little. Some atheists are extraordinarily important to our understanding of faith. The best of the atheists will allow the faith of religious and spiritual folks to flourish with new ideas.

Although this is a interesting and more-or-less unusual idea as to what "makes us human" it unfortunately turns a blind eye to those with significant mental disabilities and ultimately helps to perpetuate the stereotype that such persons are not fully human.

Moreover, although it is alluring to try to propose "Quality X" as being the definitive characteristic which makes us human, I shudder each time some brilliant person wants to suggest that a mental capacity is what separates humans from other animals.

Now, maybe there is such a thing as "Quality X" that distinguishes us as humans apart from other animals, but lets make sure it is one that really speaks for ALL humans - not just ones with university degrees.

Lastly, with a number of your programs touching on or directly focusing upon those with mental disabilities, I'm baffled as to why you wouldn't pick up on this in your post, Trent, and note this as a problem with Sapolsky's notion.

In the end, if we accept Sapolsky's idea we are just finding another (apparently) sophisticated way to keep those with significant mental disabilities in the "sub-human" category – which seems not the least bit enlightened or humane. Maybe you folks need to go re-listen to your own episode with Jean Vanier or read some of Stanley Hauerwas' writings.

How does the ability to hold conflicting thoughts without needing to resolve them or have one be the winning thought exclude anyone?If it does exclude a category of thinker, it would be those with exceedingly analytical or hyper rational minds -those who need a resolution, a hierarchy of ideas and always a right answer. The 'yes and'understanding of thought and life is a Buddhist idea and has nothing to do with mental ability, in fact the opposite.Accepting more than one perspective as valid and even holding conflicting ideas simultaneously is friendly to those with 'mental disabilities'. I think perhaps Mr Bergerud has just misunderstood the notion that Robert Sapolsky is proffering.

Most definitely, have the Doctor on. I value your show as a forum where ideas and beliefs are welcome and where exclusivity is unpopular. I value his recognition of our paradoxical nature within his beliefs. You have my vote!

Oh the irony of telling a graduating class, (paraphrasing) "It's impossible for you to change the world, which, as a human, you interpret that as possible and attractive, so get out there and delude yourself for the rest of your meaningless life."

I agree with William WWG. Robert Sapolsky would be a brilliant guest to be interviewed by the equally brilliant Krista Tippet. On Being consistently delivers intellectually stimulating conversation. In addition, I love your posts Trent. They enlighten and delight!

Dr. Sapolsky has observed and reflected on primates (humans and otherwise) carefully for years. He has much to say about social heirarchy and culture that comes from his excellent research. I have long thought he was perfect for this show. His notion of the desert religions follows on from Richard Rodriquz' points and deserves to explored. The most difficult part would be to select which things to emphasize. What primatology can tell us about ourselves as animals-- how we structure our social/cultural lives is gripping stuff. Maybe it would be a good time to hear about the social order of the baboons after the TB outbreak or the female jungle religions. This avid listener says 'Yay'.